WASHINGTON — The dedication of the Martin Luther King Jr. Memorial in Washington, D.C. will be postponed because of Hurricane Irene, the National Memorial Project Foundation announced late Thursday.

“The official Dedication Ceremony previously scheduled for Sunday will be moved to a date yet to be determined in September or October, 2011,” the foundation posted on its Martin Luther King Jr. Memorial Facebook page.

“We will announce those details as soon as they are available. For now, we wanted to make sure you had this new information as soon as possible. The National Prayer Service at the Basilica of the National Shrine of the Immaculate Conception on Saturday at 10am will be the final official final event of the Dedication week.”

President Barack Obama was scheduled to deliver the keynote address at the memorial’s dedication after returning Saturday from vacation on Martha’s Vineyard.

The memorial dedication was expected to draw thousands of visitors to Washington, including members of King’s family, elected officials and celebrities such as Stevie Wonder, Aretha Franklin and Jamie Foxx.